Seminar der Abteilung Strahlenschutz und Sicherheit (ASI)

The Seminar series of the PSI Department of Radiation Safety and Security (Abteilung Strahlenschutz und Sicherheit, ASI) introduces new results and developments in radiation protection, dosimetry, radioanalytics and similar topics. For more information and registration, please contact Claudia Nydegger.

Abstract: Luminescence dosimetry is a term that includes several techniques, such as thermoluminescence (TL), optically stimulated luminescence (OSL) and radiophotoluminescence (RPL). TL is used routinely at PSI for extremity (finger ring) dosimetry, and RPL is the basis of the personal dosimetry system used at PSI. In the last two and a half years the Dosimetry Group has worked to strengthen its research capabilities in the area of luminescence dosimetry and research, which includes the purchase of a LexsygSmart automated reader and the successful approval of a SNSF R’Equip project for the purchase of a sophisticated apparatus. In this talk we will discuss these new capabilities, present recent results and discoveries, and give an overview of the bright future in luminescence research that lies ahead.

Increased Uranium concentrations in ground and surface waters of the Swiss Plateau: A result of Uranium accumulation and leaching in the Molasse Basin and (ancient) wetlands? Anja Pregler, Abteilung Strahlenschutz und Sicherheit, PSI

Abstract: In this presentation I will provide an overview of the research carried out in the last 3 years as part of my PhD work which focused on naturally occurring Uranium (U) series isotope disequilibirum in phreatic water. Exceptionally high natural U concentrations in ground and surface waters were found in the western part of the Swiss Plateau. More than 100 public fountains were analyzed for their radionuclide content, revealing that increased U-238 concentrations frequently occur at the interface between the Lower Freshwater Molasse and the Upper Marine Molasse. Two springs at the northern slope of Mont Vully (20 km northwest of Berne, Switzerland) that originate from this interface exhibit the highest concentrations in U-238 and were thus monitored for almost 2 years in order to screen seasonal variations. In addition, the arable land north of Mont Vully was surveyed by gamma dose rate measurements to locate possible U accumulations underground. In order to verify the assumption that enhanced gamma dose rates are owed to an underground U accumulation, 5 shallow sediment drill cores were taken and analyzed for their U content. In the course of the present study, the origin of U concentration in ground and surface water as well as the U accumulation in soils are investigated and the relationship between the increased values is discussed.

Seminars 2018

What does it mean to be a radiometrologist at a university hospital? Claude Bailat, PhD, Institute of radiation physics, University Hospital (CHUV), Lausanne

Abstract: Radiometrology is performed in various institutions, such as PSI. In a clinical context, radiometrology can be seen as an extension of national metrology institutes or designated institutes. At IRA, radiometrology is performed at a primary and secondary level. It supports nuclear medicine as well as radiotherapy activities and developments. I propose for this talk to give you an overview of the duties of the group of radiometrology. We will detail two or three research projects to show practically what is expected of radiometrologists in a clinical environment.

Abstract: SwissFEL, the new FEL facility, is now under commissioning at PSI. From a radiation protection point of view, SwissFEL operation requires a permanent monitoring of the radiation level in the surroundings of the facility. This task is performed by the lately installed Dose Rate Protection System (DRPS). With the increase of the electron beam energy to 2.5 GeV, measurement campaigns have been performed in order to verify the compliance with the guidance values imposed by law in the adjacent premises to the facility and benchmark DRPS model assumptions and calibration parameters, previously derived by calculations and Monte Carlo simulations.

18 June 2018

10:30-11:30 Uhr, OFLG/402 (Coffee with speaker from 10:00-10:30)

Emergency OSL/TL Dosimetry with Components of Mobile Phones and Other Personal Items Stephen W. S. McKeever, Oklahoma State University

Abstract: Community response to large-scale radiological incidents, such as nuclear power plant accidents or terrorist attacks, requires the ability to determine the doses potentially received by individual members of the public. Normally, such individuals do not carry personal radiation dosimeters (such as TLDs, RPLDs, etc.) and therefore alternative radiation dosimetry methods need to be developed for eventual deployment following such major events. Two types of dosimetry are currently under investigation for this purpose, namely biological dosimetry (using specific biological markers for the absorption of radiation) and physical dosimetry (using radiation-induced physical markers in objects located on or near the individual). This talk will discuss the development of physical dosimetry methods, focusing primarily on luminescence (thermoluminescence (TL) and optically stimulated luminescence (OSL)) and electron paramagnetic resonance (EPR) of materials found in personal electronic devices, such as smart phones. The state-of-the-art of these research developments will be described along with projections for their potential utility.

Abstract: Many tasks associated with radiation protection, waste management and research are strongly dependent on assumptions and modeling. It is desirable to benchmark and optimize these assumptions with measurements of the neutron spectrum. A device suitable for this task is multisphere spectrometer. Such a system is currently under commissioning at PSI.This talk gives the overview of the system calibration and results of first measurements in workplace fields with high energy neutron component available at PSI.

Abstract: Tb-161 is of great interest to be used for therapeutic purposes in nuclear medicine. It provides similar decay properties as the routinely-used Lu-177 but, in addition, it emits substantial number Auger electrons. It is believed that the Auger electrons can efficiently kill small metastases or even single cancer cells. The emission of g-rays allows using the radionuclide for Single Photon Emission Computed Tomography (SPECT) which is useful for therapy monitoring and dosimetry calculations. The production and preclinical evaluation of Tb-161 have been developed at PSI. Optimization of the production process and more detailed investigation in terms of biological effectiveness are on-going. It is the aim to translate Tb-161 in clinical practice within the next few years.